It is known that the frequency response of an amplified signal entails a correlation between the frequency response of the amplitude (modulus) of the signal and the frequency response of the phase of said signal. In particular, as the band increases, the phase changes and the group delay is reduced. Group delay is defined as the derivative of the phase with respect to the frequency.
Theoretically, the desirable result is a programmable delay with an infinite band.
In applications in which it is necessary to have a delay which can be programmed according to requirements while maintaining a wide signal band, conventional circuits do not adequately maintain signal bandwidth. Such conventional circuits resort to operational-amplifier structures which require the use of control loops, with high orders of filtering, high current consumption and large semiconductor areas for their implementation. In conventional structures of the feedback type, derivative signals are introduced in high-frequency points of the circuit, thereby introducing zeros in the transfer function and producing the above-described disadvantages.